radioisotopemedical dictionary

<radiobiology> Form of a chemical element with unstable neutron number, so that it undergoes spontaneous nuclear disintegration. Major use in biology is to trace the fate of atoms or molecules that follow the same metabolic pathway or enzymic fate as the normal stable isotope, but that can be detected with high sensitivity by their emission of radiation. Also used to locate the position of the radioactive metabolite, as in autoradiography and to measure relative rates of synthesis of compounds from radioactive precursors.

This entry appears with permission from the Dictionary of Cell and Molecular Biology

(11 Mar 2008)